SCINTIGRAPHIC EVALUATION OF THE STIFLE IN NORMAL HORSES AND HORSES WITH FORELIMB LAMENESS

We tested the hypotheses that mature horses without lameness have a repeatable radiopharmaceutical uptake pattern in the stifle, which is bilaterally symmetric; immature horses have a different radiopharmaceutical uptake pattern; and forelimb lameness alters the radiopharmaceutical uptake pattern in the stifle. The objectives of the study were to describe the normal radiopharmaceutical uptake patterns using region of interest (ROI) analysis; to compare uptake patterns between left and right stifles of the same horse and between mature and immature horses; to compare radiopharmaceutical uptake in mature normal horses with those with forelimb lameness. Lateral scintigraphic images of the stifle from 51 horses aged 2-16 years were evaluated using seven ROIs and a reference site (midfemur). After subtraction of a background count, ratios between the mean counts per pixel for each ROI to the reference site were calculated. There was a repeatable radiopharmaceutical uptake pattern in mature normal horses that was bilaterally symmetrical. The caudoproximal aspect of the tibia and the patella had the highest ratios. Radiopharmaceutical uptake patterns in horses with forelimb lameness were not significantly different. Immature normal horses had a different symmetric pattern, with greatest radiopharmaceutical uptake ratios in the caudoproximal aspect of the tibia and the tibial crest. It was concluded that there are symmetric, repeatable radiopharmaceutical uptake patterns in both immature and mature horses, which are not altered by forelimb lameness.     

外源水杨酸诱导的部分甜瓜自毒作用相关基因的表达分析

以甜瓜(Cucumis melo)品种‘新银辉’为材料,采取根灌法,以水杨酸(10μmol/L)处理甜瓜幼苗,通过Real-Time PCR对叶片中部分自毒作用相关基因的表达量进行定量分析,以探究外源水杨酸诱导对甜瓜自毒作用的影响。结果显示,经外源水杨酸诱导后:(1)在催化苯丙烷类代谢途径的3个初始反应的蛋白酶编码基因中,PAL和C4H随处理后时间增加,呈逐渐上调趋势,但PAL比C4H更快响应胁迫,而4CL转录水平没有显著变化;(2)在类黄酮生物合成的3个关键酶的基因中,CHI、F3H均显示出不同程度的下调,CHS于处理后1 d略微上调,然后恢复至处理前水平;(3)两个转录因子基因WD40、R2R3-MYB分别在不同处理时间后显著下调;(4)WD40与CHI的表达相关性较高。据上述结果 ,水杨酸诱导后:(Ⅰ)CHI表达可能与转录因子WD40蛋白相关;(Ⅱ)WD40、R2R3-MYB与PAL、C4H、4CL、CHS间不存在简单、明确的调控关系;(Ⅲ)柚皮苷、表儿茶素、芦丁等甜瓜主要化感物质合成减少。     

Stormy weather in galaxy clusters

Recent x-ray, optical, and radio observations coupled with particle and gas dynamics numerical simulations reveal an unexpectedly complex environment within clusters of galaxies, driven by ongoing accretion of matter from large-scale supercluster filaments. Mergers between clusters and continuous infall of dark matter and baryons from the cluster periphery produce long-lived "stormy weather" within the gaseous cluster atmosphere-shocks, turbulence, and winds of more than 1000 kilometers per second. This weather may be responsible for shaping a rich variety of extended radio sources, which in turn act as "barometers" and "anemometers" of cluster weather.     

水稻RIL群体高密度遗传图谱的构建及苗期耐热性QTL定位

【目的】 随着全球气候变暖,高温严重威胁粮食安全,发掘耐热基因资源是培育耐高温新品种和消除高温危害最直接的绿色生态途径,也是阐明耐热生理生化和分子遗传机理的基础。【方法】 构建苗期耐热性鉴定评价方法,以热敏感品种周南稻和强耐热品种赣早籼58号杂交衍生的重组自交系（recombinant inbred lines,RIL）群体为研究材料,利用高通量测序技术对亲本和RIL群体进行全基因组测序;依据171个家系的基因型数据,利用滑动窗口法将SNP信息转换成Bin基因型,预测染色体上的重组断点,构建RIL群体高密度BinMap遗传图谱,结合耐热表型数据,运用QTL IciMapping软件完备复合区间ICIM的作图方法,进行高温胁迫下幼苗存活率和耐热等级QTL分析。【结果】 构建了一张包含3 321个Bin标记高密度遗传图谱,各染色体Bin标记数为159—400个,标记间平均物理距离为106 kb;利用逐步高温胁迫方式鉴定亲本和RIL家系幼苗耐热表型,高温胁迫下,幼苗存活率和耐热等级存在极显著负相关性,且幼苗存活率与籼型基因频率存在显著正相关性,籼型基因频率越高,耐热性越好,RIL群体表型性状呈现双峰连续分布,苗期耐热性可能受少数几个主效QTL调控;共检测到12个苗期耐热性相关的QTL,其中,调控幼苗存活率和耐热等级的QTL分别有8和4个,幼苗存活率和耐热等级相关QTL存在遗传重叠现象,形成调控耐热性的主效QTL簇qHTS2、qHTS7和qHTS8,三者在调控苗期高温抗逆中具有重要作用,其中,qHTS7为新发现主效QTL,对增强苗期耐热性具有较强的功效。【结论】 构建了一张包含3 321个Bin标记的高密度分子遗传图谱,解析了耐热品种赣早籼58号苗期耐热基因,鉴定出3个苗期耐热调控关键QTL簇,发掘了一个新主效QTL簇qHTS7,基于高密度遗传图谱高效获取目标区段及候选基因,筛选出8个苗期耐热性调控的关键目标基因。     

Diffuse Extreme-Ultraviolet Emission from the Coma Cluster: Evidence for Rapidly Cooling Gases at Submegakelvin Temperatures

The central region of the Coma cluster of galaxies was observed in the energy band from 0.065 to 0.245 kiloelectron volts by the Deep Survey telescope aboard the Extreme Ultraviolet Explorer. A diffuse emission halo of angular diameter approximately 30 arc minutes was detected. The extreme-ultraviolet (EUV) emission level exceeds that expected from the x-ray temperature gas in Coma. This halo suggests the presence of two more phases in the emitting gas, one at a temperature of approximately 2 x 10(6) kelvin and the other at approximately 8 x 10(5) kelvin. The latter phase cools rapidly and, in steady state, would have produced cold matter with a mass of approximately 10(14) solar masses within the EUV halo. Although a similar EUV enhancement was discovered in the Virgo cluster, this detection in Coma applies to a noncooling flow system.     

模拟盐渍化对甜瓜种子萌发和幼苗生理特性的影响

为了解盐渍化对甜瓜种子萌发的影响,本研究以甜瓜品种‘新银辉’为材料,采用NaCl和NaHCO₃单独处理和复合处理模拟盐渍化,观测不同处理下甜瓜种子萌发情况以及生理生化指标的变化。结果表明:NaCl、NaHCO₃、NaCl和NaHCO₃复合处理模拟的盐渍化几乎都对甜瓜种子萌发产生了抑制作用,胁迫浓度越高,抑制作用越明显;仅低浓度（50 mmol/L）的NaCl表现出一定的促进作用。NaCl和NaHCO₃复合处理后甜瓜种子萌发过程中超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性随着处理时间增加,呈升-降-升的趋势;过氧化物酶（POD）活性先上升后下降;脯氨酸（Pro）含量持续上升;可溶性糖含量持续下降;丙二醛（MDA）含量始终显著高于蒸馏水对照;淀粉含量随着处理时间增加呈下降的趋势,α-淀粉酶活性和β-淀粉酶活性均呈先下降、后上升的趋势。模拟盐渍化明显抑制甜瓜种子的萌发和幼苗生长,保护酶活性、淀粉代谢在应对胁迫中起到了明显作用,研究结果有助于为甜瓜耐盐机制和设施栽培提供有益的参考。     

芥蓝TCP家族全基因组鉴定及表达分析

为明确芥蓝TCP家族相关基因在叶片发育中的功能,基于甘蓝基因组数据,分析鉴定出芥蓝TCP基因家族有40个成员,参考拟南芥同源TCP基因注释及拟南芥数据库基因的相对表达量,初步选取BoTCP21和BoTCP25基因,采用qRT-PCR分析。结果表明：BoTCP21和BoTCP25均在叶片中大量表达,但二者在真叶不同部位的表达模式存在差异。为了进一明确TCP基因家族中参与叶片发育的基因,采用生物信息学方法并结合qRT-PCR对BoTCP家族进行了全面分析。结果显示：40个BoTCP都属于非分泌亲水性蛋白,分别定位在8条染色体上;系统进化树构建和亲缘关系分析将芥蓝中的BoTCP成员归为3类,其中PCF亚家族有19个成员,CYC亚家族8个成员,CIN亚家族13个成员。qRT-PCR结果表明：BoTCP21和BoTCP25在真叶和薹叶中具有较高的表达量,BoTCP14在开花结荚的植株根部表达量较高,而BoTCP16则在抽薹植株的根部表达量最高,说明BoTCP家族成员在组织部位表达存在时空特异性且广泛参与了植株的形态建成和器官发育。     

The toxicity of Castanospermum australe seeds for cattle

Two calves given a mean of 16.1 g and 16.4 g ripe Castanospermum australe seeds/kg body weight daily for 13 and 16 days respectively developed haemorrhagic gastroenteritis. The first calf died. The second calf had mild myocardial degeneration and necrosis and mild nephrosis at necropsy. Two calves given a mean of 16.8 g unripe C. australe seeds/kg body weight daily for 18 days remained clinically normal and had mild gastritis at necropsy. The activity of alpha-glucosidase was reduced in the mononuclear cells of peripheral blood and in skeletal muscle. This was attributed to the presence of the indolizidine alkaloid, castanospermine, in the seeds. The toxin causing the gastroenteritis and other lesions is unknown.     

Further investigation of lead exposure as a potential threatening process for a scavenging marsupial species

There is a growing recognition of the harmful effects of lead exposure on avian and mammalian scavengers. This can lead to both lethal and non-lethal effects which may negatively impact wildlife populations. Our objective was to assess medium-term lead exposure in wild Tasmanian devils (Sarcophilus harrisii). Frozen liver samples (n = 41), opportunistically collected in 2017–2022, were analysed using inductively coupled plasma mass spectrometry (ICP-MS) to determine liver lead concentrations. These results were then used to calculate the proportion of animals with elevated lead levels (>5 mg/kg dry weight) and examine the role of explanatory variables that may have influenced the results. The majority of samples analysed were from the south-east corner of Tasmania, within 50 km of Hobart. No Tasmanian devil samples were found to have elevated lead levels. The median liver lead concentration was 0.17 mg/kg (range 0.05–1.32 mg/kg). Female devils were found to have significantly higher liver lead concentrations than males (P = 0.013), which was likely related to lactation, but other variables (age, location, body mass) were not significant. These results suggest that wild Tasmanian devil populations currently show minimal medium-term evidence of exposure to lead pollution, although samples were concentrated in peri-urban areas. The results provide a baseline level which can be used to assess the impact of any future changes in lead use in Tasmania. Furthermore, these data can be used as a comparison for lead exposure studies in other mammalian scavengers, including other carnivorous marsupial species.